script to quickly filter out domains that either don't exist or are down

pingcheck.py

import subprocess, sys, os                                                                                  
                                                                                                                                                                                              
dev_null = open(os.devnull, 'w')                                                                            
                                                                                                            
up = []                                                                                                     
                                                                                                            
with open(sys.argv[1], 'r') as handle:                                                                      
                                                                                                            
    while True:                                                                                             
                                                                                                            
        curr = handle.readline()                                                                            
                                                                                                            
        if curr == "":                                                                                      
            break                                                                                           
                                                                                                            
        curr = curr.strip()                                                                                 
                                                                                                            
        c = subprocess.Popen(["ping", curr, '-W', '2', '-c' '1'], stdout=dev_null, stderr=subprocess.STDOUT)
        c.communicate()                                                                                     
        if c.returncode == 0:                                                                               
            up.append(curr)                                                                                 
            print(f"found: {curr}")                                                                         
                                                                                                            
open("out.txt", 'w').write('\n'.join(up))